Moog Theremini Melds Analog & Digital

PORTLAND, Ore. — Robert Moog invented the voltage controlled oscillator (VCO) -- the primary building block of all analog music synthesizers, including the legendary Moog synthesizer itself. But he began to be interested in music electronics in the 1950s when he was in high-school. In particular he idolized the theremin -- that eery-sounding instrument that musicians control by moving their hands in midair around a telescopic "antenna."

Now Moog Music Inc. has not only resurrected the theremin -- now called the Theremini -- but has improved it immeasurably with a built-in synthesizer, control outputs to link it to other synthesizers, and a music instrument digital interface (MIDI) to control all functions from a Mac, Windows, or iPad.

"Basically we took the classic theremin -- using its heterodyne antenna -- with the person's hand acting as the grounded pad of a capacitor," David Molnar, Moog senior design engineer told EE Times. "You only get about a picofarad in change, but that's enough to sweep you through a whole range of sounds."

Renowned thereminist Dorit Chrysler playing Moog's Theremini from a bank of music synthesizers.
(Source: Moog Music)

The original theremins were all analog, but in order to reduce the price from $799 to $299, Moog Music used a digital signal processor (DSP) to do the heavy lifting in the sound generation of the Theremini. The DSP chosen was from Texas Instruments (TMS 320 S 2069 U). The Teremini has two antennas, one the heterodyne described above, which controls pitch, and a second smaller one to control volume whose output runs directly into the DSP. The Theremini has a built-in speaker and a headphone jack.

"In the new Theremini we run the volume control signal directly into the DSP, which allows us to quantize the pitch with a knob," says Molnar. "If you turn it fully on, you only get notes off your chosen scale, which makes it really easy to play -- especially for children and people who are just learning."

According to Molnar, a traditional theremin is very difficult to learn to play, because you are just waving you hands in the air instead of pushing keys on a piano or strings against the frets of a guitar, which automatically quantize the notes. As users gain experience playing the Theremini, however, they can also turn quantization down, say half way, and then use slight movements of your hands and fingers to bend notes and add vibrato.

The Theremini has a small ring antenna (left) to control column and a telescoping vertical antenna (right) for controlling the pitch of a single note or any parameter in the internal or an attached music synthesizer.
(Source: Moog Music)

Moog Music's Theremini is assembled in the US by a single person who is responsible for its (hopefully) high quality rating. (Source: Moog Music)

To add an entire synthesizer inside the Theremini, Moog Music ported the entire Animoog software synthesizer from the iPhone to the DSP inside the Theremini. The Theremini also has Moog's famous delay function built-in so that users can add echo effects to their musical creations.

For the future, the next improvement will be an upgrade for the firmware that will add new capabilities that early uses have asked for. The team is also working on apps for Mac, Windows, and iPad that will allow users to easily edit all the parameters in the Theremini and load them in user presets over USB.

Doctor Who's intro was originally produced by Deliah Derbeyshire, assisted by Dick Mills, from a score by Ron Grainer, in the BBC Radiophonic Workshop. It was completed before the September 1963 airing of the first episode (obviously). Robert Moog did not produce a synthesizer (the first electronic subtractive, voltage-controlled synthesizer) until after he demonstrated his prototype at the AES conference in October of 1964. Although Moog had been designing and making (and publishing articles in Radio-Electronics and selling kits for) theremins since the early 1950's, the Doctor Who theme did not use one.

Instead, Derbyshire and Mills used banks of oscillators and white noise, coupled with Music Concrete processes to make the theme music. They recorded each sound on tape, adjusted and rerecorded to get all the reqired pitches, hand-tuned oscillator dials to get the sweeping melody, etc, then literally cut and taped together the sounds to produce the master tape. Although further editing was attempted, few of the results were used (one was used and later rejected, causing many of the video tapes to be re-written to eradicate the changed version.

The original Derbyshire/Mills version had an amazingly long life, despite licensing problems related to Grainger's death. Major changes usually involved adding live sound (orchestras, for instance), but it wasn't untll the 1980's when Radiophonic staffer Peter Howell recorded a new version, using analog synths by Roland, ARP and Yamaha supplemented by an EMS Vocoder.

In short, Doctor Who's theme has never been affected by a theremin directly or one of Dr. Moog's VCOs or synthesizers, at all.

Theremini is the true reincarnation of the "AirGuitar" that would even make Keith Emerson proud, especially since he is right handed. I am surprised that the masterminds at Moog forgot to make the control interface ambidextrous.

What a simple yet wonderful instrument that even your cat or your dog could play, without knowing what a picoFarad is. For the silly price of $300, this device is a great introduction to the concepts of pitch and volume to a toddler, in the hopes that s/he don't become a hacktivist first!

Thanks for the comment. Yes, there were earlier uses of the voltage-controlled oscillator for RF and such. Lets say he developed the VCO for the analog synthesizer. Thanks again for the careful reading.